The present invention relates to a shifting apparatus for controlling a transmission in a vehicle and, more particularly, for controlling a shifter that controls the transmission of a drag race vehicle.
In the sport of automotive drag racing (which includes, drag racing, mud racing, sand racing, hill racing, and the like), automatic transmissions are converted with manual shift valve bodies with transbrakes (transmission brakes). The transbrake is used to hold the vehicle on the starting line through a solenoid attached to the valve body. Some vehicles are provided with a "roll control" solenoid that locks the brakes on the vehicle, acting in much the same manner as a transbrake. These solenoids are activated by a hold button, most often found on the steering wheel. A shifter is connected through a cable to the transmission controlling the valve body. The shifter is controlled manually by the driver when the tachometer reaches the rpm (revolutions per minute) level desired by the driver. The shifter can also be controlled by a pneumatic cylinder or an electric solenoid freeing the driver's hands. Manufacturers now offering this type of shifter control include Shifnoid (Columbus, Ohio), Dixie (Boone, N.C.), Dedenbear (Pleasant Hill, Calif.), and Advanced Control Devices (Alburtis, Pa.). The cylinder or solenoid is electronically connected through a control valve or a relay that is activated by a button or an rpm switch. This rpm switch is preset at the desired shift level. The shifter control is activated each time the desired rpm level is reached.
A multiple number of cylinders or solenoids can be attached to an in-line shifter activating each shift or gear change. Each cylinder or solenoid must have its own rpm switch set at the desired rpm level. The rpm switch for the first shift must be set at a lower rpm level than the rpm switch for the second shift, and so forth for each succeeding higher gear. Alternatively, a single cylinder or solenoid can be attached to a ratchet shifter controlling a multiple number of shifts at one rpm level. Advance Control Devices and Dixie are two manufacturers of pneumatic cylinder shifter controls for ratchet shifters.